AEMC instruments GROUNDFLEX 6474 User manual

6474
User Manual
ENGLISH
GROUNDFLEX®ADAPTER
WITH AEMC
®
INSTRUMENTS

Statement of Compliance
Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments
certifies that this instrument has been calibrated using
standards and instruments traceable to international
standards.
We guarantee that at the time of shipping your
instrument has met its published specifications.
NIST traceable calibration is only possible when
the Model 6474 is connected to the Ground Tester
Model 6472.
To obtain NIST calibration (for a nominal charge), the
instrument would need to be returned to our facility,
along with your Ground Tester Model 6472.
The recommended calibration interval is 12 months
and begins on the date of receipt by the customer. For
recalibration, please use our calibration services. Refer
to our repair and calibration section at www.aemc.com.
Serial #: ________________________________
Catalog #: 2136.03
Model #: 6474
Please fill in the appropriate date as indicated:
Date Received: _________________________________
Date Calibration Due: _______________________
Chauvin Arnoux®, Inc.
d.b.a AEMC®Instruments
www.aemc.com

2 GroundFlex®Adapter Model 6474
Table of Contents
INTRODUCTION ..................................................................................... 3
1.1 International Electrical Symbols...........................................................4
1.2 DenitionofMeasurementCategories.................................................4
1.3 ReceivingYourShipment.....................................................................4
1.4 OrderingInformation ............................................................................5
1.4.1 AccessoriesandReplacementParts......................................5
GROUNDFLEX®ADAPTER ...................................................................... 6
2.1 ControlFeatures ..................................................................................6
2.2 GroundFlex®Sensor ............................................................................7
2.2.1 CalibrationofGroundFlex®Sensors .......................................8
2.3 MeasurementsinAUTOMode...........................................................10
2.3.1 PreparationoftheGroundFlex®Adapter...............................10
2.3.2 MakingaMeasurement(ResistanceofLegs) ......................12
2.3.3 OtherMeasurements ............................................................14
2.4 MANUALModeandSWEEPMode ...................................................14
2.5 TowerTestingMeasurement ..............................................................16
2.5.1 ChoosingthepositionsfortheH,Selectrodes:....................16
SPECIFICATIONS................................................................................. 24
3.1 Electrical.............................................................................................24
3.2 Mechanical.........................................................................................26
3.3 Environmental ....................................................................................26
3.4 Safety.................................................................................................26
MAINTENANCE ................................................................................... 27
4.1 Maintenance.....................................................................................27
4.2 Cleaning...........................................................................................27
RepairandCalibration.................................................................................28
TechnicalandSalesAssistance ..................................................................28
LimitedWarranty .........................................................................................29
WarrantyRepairs ........................................................................................29

GroundFlex®Adapter Model 6474 3
CHAPTER 1
INTRODUCTION
WARNING
Thesesafetywarningsareprovidedtoensurethesafetyofpersonnel.
Pleaseread and complywiththeseprecautions:
• Thisinstrumentisprotectedfromaccidentalvoltagesofnotmorethan
50VwithrespecttoearthinmeasurementCATIV.Theguaranteedlevel
ofprotectionofthisequipmentmaybecompromisedifusedinamanner
notspeciedbythemanufacturer.
• Safetyistheresponsibilityoftheoperator.
• Allmetalobjectsorwiresconnectedtotheelectricalsystemshouldbe
assumedtobelethaluntiltested.Groundingsystemsarenoexception.
• Never exceed the maximum rated voltage and current, and the
measurementcategory.
• Never exceed the protection limits, and always comply with the
conditionsandplaceofuse,indicatedinthespecications.
• Donotusetheinstrumentoritsaccessoriesiftheyappeardamaged.
• Useaccessories that haveovervoltagecategory and service voltages
greaterthanorequaltothoseoftheinstrument(CATIV50V).Useonly
accessoriesthatcomplywithsafetystandards(IEC61010-2-031&32).
• Weartheappropriateprotectivegear(insulatingbootsandgloves).
• CheckthatnoterminalisconnectedandtheswitchissettoOFFbefore
openingthedevice.
• Useonlythechargingunitsuppliedwiththeinstrumenttorechargethe
battery.
• Troubleshootingandmetrologicalvericationproceduresmustonlybe
performedbyqualied,approvedpersonnel,orthefactory.
• NOTE: Thepotentialsonthevariousrodsusedforanearthmeasurement
maybedi󰀨erentifanearbyelectricalinstallationisdefectiveorcertain
weather conditions prevail (thunderstorms). It is up to the operator
to decide whether to continue or postpone measurements in these
situations.

4 GroundFlex®Adapter Model 6474
1.1 International Electrical Symbols
Signifies that the instrument is protected by double or reinforced insulation.
This symbol on the instrument indicates a WARNING that the operator must
refer to the user manual for instructions before operating the instrument. In
this manual, the symbol preceding instructions indicates that if the instructions
are not followed, bodily injury, installation/sample and/or product damage may
result.
Risk of electric shock. The voltage at the parts marked with this symbol may be
dangerous.
Ground/Earth symbol
In conformity with WEEE 2002/96/EC
1.2 Definition of Measurement Categories
CAT II: Formeasurementsperformedoncircuitsdirectlyconnectedtotheelectrical
distributionsystem.Examplesaremeasurementsonhouseholdappliancesor
portabletools.
CAT III:
Formeasurementsperformedinthebuildinginstallationatthedistributionlevel
suchasonhardwiredequipmentinxedinstallationandcircuitbreakers.
CAT IV: Formeasurementsperformedattheprimaryelectricalsupply(<1000V)such
asonprimaryovercurrentprotectiondevices,ripplecontrolunits,ormeters.
1.3 Receiving Your Shipment
Uponreceivingyourshipment,makesurethatthecontentsareconsistentwiththe
packinglist.Notifyyourdistributorofanymissingitems.Iftheequipmentappears
tobedamaged,leaclaimimmediatelywiththecarrierandnotifyyourdistributor
atonce,givingadetaileddescriptionofanydamage.Savethedamagedpacking
containertosubstantiateyourclaim.

GroundFlex®Adapter Model 6474 5
1.4 Ordering Information
NOTE: The GroundFlex®Adapter Model 6474 only operates in combination
with the Ground Tester Model 6472 Kit - 500ft.
GroundFlex®Field Kit (Model 6472 and 6474) .............................Cat. #2136.03
Includes: (Ground Tester Model 6472 Kit-500 ft (Cat #2135.54)); Model 6472, one carrying bag,
two 500 ft. color-coded leads on spools (red/blue), two 100 ft. color-coded leads (hand tied,
green/black), one 30 ft. lead (green), two 5 ft. color-coded leads (red/blue), 100/240V power
adapter with US power cord, optical USB cable, four T-shaped auxiliary ground electrodes,
set of ve spaded lugs, one 100 ft. tape measure, rechargeable NiMH battery pack, USB stick
with DataView software, ground tester workbook and user manual. GroundFlex® Adapter
Model 6474, four GroundFlex® sensors (5m), twelve color-coded rings, connection lead, two
extension leads on H reel (black/green) with color-coded alligator clips, one extra green and
black alligator clips, two BNC extension leads, calibration loop, three C-clamps, set of 2-reel
caddy’s, one inverter 12VDC to 120VAC watt (vehicle use), carrying case with wheels and
handle for meters and user manual.
1.4.1 Accessories and Replacement Parts
Bag#6-CarryingBagforGroundKits............................................. Cat. #2119.82
TapeMeasure-AEMC®(100ft) .......................................................Cat. #2130.60
Setoftwo,14.5"T-shapedAuxiliaryGroundElectrodes..................Cat. #2135.39
OpticalUSBCable............................................................................Cat. #2135.41
Replacement-ConnectionLeadforModel6472/6474.................... Cat. #2135.75
Replacement-OneBNC(15m/50ft)ExtensionLead...................... Cat. #2135.76
Replacement-Setof12,GroundFlex®Rings
(red,yellow,brown,orange) .............................................................Cat. #2135.77
Replacement-GreenExtensionLead .............................................Cat. #2135.78
Replacement-BlackExtensionLead...............................................Cat. #2135.79
Replacement-Setof3,C-clamps....................................................Cat. #2135.80
Replacement-CalibrationLoop....................................................... Cat. #2135.82
Replacement-CarryingCase ..........................................................Cat. #2135.83
Replacement-OneGroundFlex®(5m /16ft)Sensor.........................Cat. #2135.92
Replacement-SafetyAlligatorClip(black) ......................................Cat. #5000.99
Replacement-SafetyAlligatorClip(green) .....................................Cat. #5100.06
GroundFlex®Sensor10M.................................................................Cat. #2135.87
Order Accessories and Replacement Parts Directly Online
Check our Storefront at www.aemc.com/store for availability

6 GroundFlex®Adapter Model 6474
CHAPTER 2
GROUNDFLEX®ADAPTER
2.1 Control Features
50V CAT IV
1-2-3-4
1-2-3
1-2
1
2
3
4
For Use with the
Ground Tester Model 6472
GroundFlex
®
Sensor
SENSOR TURNS
SENSITIVITY
To Model 6472
Overload
INPUT
1
2
3
4
GroundFlex®Adapter
MODEL 6474
2
4
1
6
5
3
1. Inputs1through4forGroundFlex®sensors
2. ConnectorforconnectionleadtotheGroundTesterModel6472
3. OVERLOADindicator
4. SENSORTURNSselector:1,2,3or4
5. SENSITIVITYselector:x10,x1orx1/10
6. INPUTSELECTION:1,2,3,4,1-2,1-3or1-4

GroundFlex®Adapter Model 6474 7
2.2 GroundFlex®Sensor
TheGroundFlex®sensorsareplacedaroundaconductor(towerlegorpole)and
closed using a screw connector, which is part of the sensor. This closed loop
is then used to make a contact-free measurement of the current owing in the
conductor(leg)itiswrappedaround.
Thesesensorsarecurrentmeasurementclampsbutareabletoencloseobjects
thataremuchlarger.
GroundFlex®sensorsareavailableinlengthsofuptoapprox24ft(8m)andcan
beplacedaroundobjects(suchastowerlegs)uptoinapprox8ftdiameter(2.7m).
50V CAT IV
1-2-3-4
1-2-3
1-2
GroundFlex
®
Sensor
To Model 6472
Overload
INPUT
1
2
3
4

8 GroundFlex®Adapter Model 6474
2.2.1 Calibration of GroundFlex®Sensors
Calibrationisnecessaryforanewsensor,onethatisnolongeridentiedwhena
sensorhasbeenreplaced,ormorethan2lengthsofextensioncableisused.The
calibrationcoe󰀩cientsarethenstoredintheModel6474.
NOTE: Do not move or touch the GroundFlex®sensor or the calibration loop
during the calibration. This could cause errors.
Startbyidentifyingeachsensorusingtheidenticationringsthataresuppliedwith
theModel6474:(1)Brown (2)Red (3)Orange (4)Yellow
• ConnectthecalibrationloopbetweenterminalsHandEoftheModel6472.
• ConnecttheModel6472and6474togetherusingtheconnectioncable.
• ConnecttheGroundFlex®sensorwiththeBrownringtoInput1oftheModel
6474,theonewiththeRedringtoInput2,theonewiththeOrangeringtoInput
3,andtheonewiththeYellowringtoInput4.
• CoiltheGroundFlex®sensorfourtimesaroundinthecalibrationloopandclose
itusingitsscrewconnector.Placetheconnectorasfaraspossiblefromthe
calibration device.
6472 6474

GroundFlex®Adapter Model 6474 9
1. Settheswitchofthe6472toSET-UP.
2. SettheSENSOR TURNSswitchto4.
3. SettheSENSITIVITYswitchtox1.
4. SettheINPUT SELECTIONswitchto1.
1-2-3-4
1-2-3
1-2
1
2
3
4
SENSOR TURNS
SENSITIVITY INPUT
5. PresstheHz/OPTIONSbutton5times.
 ThedevicestartsbycomparingthecurrentIIntinjectedbythedeviceintothe
calibrationlooptothecurrentIAmeasuredbytheGroundFlex®sensor.Ifthey
aredi󰀨erent,the"CAL"symbolblinkstorecommendacalibration.
x 5
4
H
E
S x 11
AUTO
mA
m A
NOTE: To avoid measurement errors, do not touch the GroundFlex®sensor or
the calibration loop during the calibration.

10 GroundFlex®Adapter Model 6474
6. Tostartthecalibration,press2nd + START.
7. Thedevicecalculatesandstoresacalibrationcoe󰀩cientfortheGroundFlex®
sensorconnectedtochannel1.
4
H
E
S x 11
AUTO
mA
m A
Thisoperationmustberepeatedforchannels2,3and4;theINPUT SELECTION
switchmustbesettothecorrespondingpositioneachtime.
Thecalibrationvaluesarenowstoredintomemory.
After calibration, the GroundFlex® sensors must always be connected to their
respectivechannels.
NOTE: Always connect the same sensor to the same input.
2.3 Measurements in AUTO Mode
2.3.1 Preparation of the GroundFlex®Adapter
TheGroundFlex®AdapterModel6474isdesignedtobeusedonlywiththeModel
6472device.Thetwoinstrumentsmustbeconnectedusingthespecialconnection
cablesupplied.TheModel6474hasnoON/OFFbutton,andispoweredonlyby
theModel6472,viathisconnectioncable.
TheModel6474is intendedprimarilytomeasurethecurrentthatowsthrough
ahigh-voltagetowertotheground.Youcanwrapupto4legsofthetowerseach
withaGroundFlex®sensorandmeasurethecurrentowingtoearththrougheach
ofthelegsorthroughseverallegs.
1. SettherotaryfunctionswitchtoGroundFlex®ontheModel6472.
 WhenyouconnecttheGroundFlex®AdapterModel6474tothe6472,aself-
testwillbegin.Duringthistest,theOVERLOADchecklightonthe6474islit.
2. Connecttherequirednumberofsensorstochannels1,2,3,and/or4.

GroundFlex®Adapter Model 6474 11
NOTE: • The sensors have arrows to indicate a direction.
• All sensors should face the same direction.
(clockwise or counter-clockwise around the tower legs)
• All sensors should have the same number of wraps.
• Sensors should encircle both leg AND ground system.
6474
To the Model 6472
3. OntheModel6474,settheINPUT selectionswitchaccordingly.Youcanmea-
surethe currentowingthrough one GroundFlex®sensor (1, 2,3,or 4),or
throughseveralsensors(1,2or1,2,3),orthroughallofthesensors(1,2,3,
4).
4. Select how many times the sensor is wrapped around the conductor to be
measured(from1to4turns)usingtheSENSOR TURNSselectionswitch.
NOTE: To increase measurement sensitivity, we recommend when possible,
wrapping a maximum number of turns (up to 4) around the structure.
5. SettheSENSITIVITYswitchtothedesiredsensitivity:x1/10,x1,orx10.The
choiceofsensitivitydependsontheexpectedcurrentvalue.Asaprecaution,
alwaysstartwiththelowestsensitivity,x1/10,andincreaseitasneeded.

12 GroundFlex®Adapter Model 6474
2.3.2 Making a Measurement (Resistance of Legs)
1. PlaceauxiliaryelectrodesH (Z) and S (Y)onoppositesidesofthetower,as
farawayaspossible(100-150ft)and,ifpossible,perpendiculartothehigh-
voltageline(depthisnotimportant).Thiswilleliminateinterferencewiththe
measurementby stray voltages or currents induced underthehigh-voltage
line.
NOTE: The H (Z) and S (Y) electrodes can be placed in the same direction
if necessary. In this case, the S (Y) electrode should be placed at 62% the
distance of H (Z).
2. In order to avoid electromagnetic interference, it is best to unwind the full
lengthofeachcablefromthereel,tokeepthecablesasfarapartaspossible
ontheground,takingcarenottoformloops,andtoavoidplacingthecables
nearorparalleltometallicconductors(cables,rails,fences,etc.).E󰀨ectsof
interferencearemeasuredinmilli-ohms.
3. Connectthese auxiliary electrodes to the terminals H (Z) and S (Y) onthe
Model6472'sfrontpanel.
4. Important: TheterminalsES (Xv) and E (X)mustbeconnectedtoaconduct-
ingmetallicpartofthetowerlocatedabovetheGroundFlex®sensors.This
ensuresmeasurementofthecurrentowingdownwardandtowardstheearth
(otherwise,youwouldmeasurethecurrentowingupward,fromtheearthto
thetopofthetower).
Thiswilltelltheconditionoftheoverheadgroundconductor.
5. Connect the required number of GroundFlex® sensors to channels 1, 2, 3,
and/or4(thechannelsforwhichtheyarecalibrated)andplacetheGround-
Flex®sensorsaroundthelegsofthetower.
NOTE: The direction of coiling of the sensors around tower legs have no
effect on the measurement, but all of the GroundFlex®sensors must be
coiled in the same direction and have the same orientation (check arrow
direction on the sensor) and they must all have the same number of turns.
Sensors should encircle both leg AND ground system.

GroundFlex®Adapter Model 6474 13
E
S
H
RS
RH
ES
1
2
3
4
6474
6472
Overhead earth wire
High-voltage
lines
4 GroundFlex®sensors
connected with the
same orientation
WARNING: If the GroundFlex®Adapter Model 6474 is connected to the earth
tester, the earth potential connected to the terminals E (X) and ES (Xv) will
also be present at the BNC connectors of the GroundFlex®sensors and at the
connecting cable between the adapter and tester. Whenever any doubt exists
about this earth potential, the user should proceed to a voltage measurement
using the S (Y) and ES (Xv) terminals of the tester.
1. Setthe3switches(Inputs,TurnsandSensitivity)oftheGroundFlex®Adapter
accordingtotheconnectionmade.
2. StartthemeasurementbypressingtheSTART/STOPbutton.
1
AUTO
k Ω
mA
V
H
S
ES
E
S x 12
Todisplaythemeasurementparameters,pressDISPLAY several times.

14 GroundFlex®Adapter Model 6474
Thedevicedisplaysthefollowingparameters:
RSEL,US-ESanditsfrequency,ISEL,R-Act(RPASS),U-Act(US-ESanditsfrequency,
UH-Eanditsfrequency),I-Act(ISELanditsfrequency).
TomeasuretheresistancesofelectrodesH (Z) and S (Y),oriftheresistanceof
theelectrodesistoohigh,startthemeasurementbyalongpress(approx2sec)of
theSTART/STOPbutton(youwillheara2ndbeep).
RH,RS,UH-E,IH-Ewillbedisplayed.
2.3.3 Other Measurements
AsexplainedinStep4onthepreviouspage,terminalsES (Xv) and E (X)mustbe
connectedtoametallicpartofthetowerabovetheGroundFlex®sensor in order to
measurethecurrentowingISELdownwardthroughthesensortowardstheearth
tomeasuregroundresistanceoftheleg.
IfconnectionsES (Xv) and E (X)areplacedbelowtheGroundFlex®sensor,the
lattermeasuresthecurrentowingtowardsthetopofthetowerviatheoverhead
groundconductoratitstop,andyoucaninthiswayevaluatethequality of this
overhead ground conductor.
You can even make this measurement without moving the contacts of ES (Xv)
and E (X) on the tower by simply passing the 2 connecting cables through the
GroundFlex®sensor.ThecurrentinconnectingcableE(X) andthecurrentthrough
thelegofthetowerthencanceleachotherout.
Youcanalsomeasureany leakage currents(I-Act)owingthrougheachlegof
thetowerinnormaloperationofthehigh-voltageline.Ifyounddi󰀨erentleakage
currentsineachleg,buttheycanceloutwhenaddedtogether,youcanconclude
thatthesecurrents,inducedbytherotatingeldofthehigh-voltagelines,indicate
an earthing faultofthetowervia the overhead ground wire at the tip of the
mast.
2.4 MANUAL Mode and SWEEP Mode
Use the Hz/OPTIONS button and ► button to change to MANUAL mode. The
followingparameterscanbemodied:
• 128Hzblinks Changethetestfrequency
• Testvoltageblinks Switchbetween10,16,32and60V
Youcanalsoperformafrequencysweepandasmoothing.

GroundFlex®Adapter Model 6474 15
Inthesweepmode,themeasurementscanbemadeatfrequenciesupto5kHz.
Onasingletower,frequenciesintheorderof5kHzdonotalwaysentailinductive
e󰀨ects, but the "current loops" formed by the adjacent towers and the return
channelthroughthegroundmayresultininductancesthatcanbedetectedonly
athighfrequencies.
Anequivalentdiagramofthecomponentsformingthiscircuitisasfollows:
Point of injection
of the current
Overhead
earth wire
LLL
Rpylon
Next pylon
to the left
Pylon
measured
Next pylon
to the right
A measurement in sweep mode (SWEEP) of an installation like this having 10
towersgivesthefollowingresultsassuminganearthresistanceRpylon of10Ωfor
eachtowerandaninductanceLof550µH for the link via the overhead ground
conductoratthetipofthetowers:
Impedance of the towers
0
2
4
6
8
10
12
14
16
0100020003000 4000 5000
F (Hz)
Z (ohm)
MeasurementofatowerearthimpedancewithGroundFlex®
sensors
Conventional4polemeasurement
Measurementintothetopofatower(iterativenetworkimpedance)

16 GroundFlex®Adapter Model 6474
2.5 Tower Testing Measurement
1. ConnectthegreenCurrent(E)andblackVoltage(ES)testleadstothe
groundingsystemtobetestedusingseparatecables.Connectionpoints
shouldbesidebysideandabovetheGroundFlex®(Rogowski)coilwhen
testingtowerlegresistanceand/orimpedance.
Figure 1
2. WraptheGroundFlex®coilsaroundthetower'sleg(s).Byincreasingthe
numberofturnsaroundthetower'sleg(s), theresultingmeasurementswill
bemorerobust. Allcoilsmusthavethesamenumberofturnsaroundeach
towerleg.
3. Installallcoilsinthesamerotationaldirection,eitherclockwiseor
counterclockwise.ThecoaxcablesontheGroundFlex®sensorshavearrows
toindicatetherotationaldirectionthatmustbeconsistentbetweentower
legs.Ontowerswith3or4legs,thesensorsmustbeinsequencefromone
legtothenext.
Figure 2
2.5.1 Choosing the positions for the H, S electrodes:
1. Ifpossible,positiontheHandSelectrodes90°totheHighVoltage(HV)line,
andplaceonetotheleftandtheothertotherightwithrespecttotheHV
transmissionline.Ifthisisnotpossible,stayatleast30°o󰀨paralleltotheHV
line.Theminimumdistanceshouldbe150–300ft(50-100m).Neverplace
anelectrodewithintheminimumdistancefromtheHVlineand/orparallelto
theHVline.
2. ConnecttheHelectrodeusingthered(H)leadandtheSelectrodeusingthe
blue(S)lead(seeFigure2).

GroundFlex®Adapter Model 6474 17
NOTE:TheresistancefortheHandSelectrodestoearthshouldeachbebelow
1kΩtoensuregoodtestresults.
Figure 3
3. Forthemostaccuratemeasurements,rollthecablecompletelyoutto
eliminateanyinductanceproblemsinlocationswithhighoverheadenergy
fromtheHVline.Normallyerrorsareinthemilliohmregionwhenthecables
arenotfullyremovedfromthespool.
4. Conrmthattheumbilicalcableconnectionbetweenthe6472and6474is
secure.Checkthepositionoftherotaryswitches(Input,SensorTurnsand
Sensitivity)onthe6474tobesuretheymatchthetestrequirements(see
Figure4).
5. Makesurethenumberofturnsbetweentowerlegsarethesame.The
numberofturnsmustcorrespondtothenumberofturnsusedontheinstalled
GroundFlex®coilsoneachtowerleg.
Figure 4
6. Useinputswitchposition"1-2-3-4"formeasurementofthetotalpylonearth
currentonfourlegtowers.Usethecorrespondingswitchpositionfor2(1-2)
and3(1-2-3)legtowers.
7. Startthetestwithx10amplication.
8. Turntherotaryswitchonthemodel6472totheGroundFlex®position.The
6474amplierwillturnonafterthe6472ispoweredonandthecalibration
oftheconnectedGroundFlex®sensorswillbeveried.TheOverloadLED
willcomeonforafewsecondsduringpowerup.IfthisLEDisashing
continuouslyandthe6472isbeepingcontinually,thenthecurrentinthe
GroundFlex®sensor(s)aretoohighfortheselectedamplication.Reduceto
X1andthentoX1/10ifnecessary.Ifitisstillpresentinthe1/10position,then
reducethenumberofturnsoftheGroundFlex®sensors.

18 GroundFlex®Adapter Model 6474
First check (see Figures 5, 6, 7, and 8):
1. PresstheDISPLAYbuttonuntilU-Act.andUS-ESorUH-Eisshown.U-Act.
referstoliveactualvoltage.US-ESequalsmeasuredvoltagebetweenSand
ES. DisturbancevoltagemeasurementsontheSProbeandtheHAuxiliary
electrodewillruncontinuouslyaslongasatesthasnotbeeninitiatedwith
theSTARTbutton.
2. PresstheDISPLAYkeyagainuntilU-Act.andUH-Eisshown.UH-Eequals
themeasuredvoltagebetweenHandE.ThefrequencyofUS-ESorUH-E
appearswhenthecorrespondingvoltageishigherthan0.1V.Themeasured
voltageiscausedbythecurrentowingthroughthetowerintotheEarth.
3. CheckifthevaluesforUH-EandUS-ESareequal.WhenUH-EequalsUS-
ES,theelectrodesareplacedfarenoughfromthepotentialinuenceofthe
towerlegs.
4. Ifoneofthevaluesissmallerthantheothervalue,youshouldrepositionthe
electrodethatshowsthesmallervoltagefurtherawayfromtheHV-lineand
checkUS-ESandUH-Eagain.
5. PresstheSTART-buttonwhenbothmeasurementsareequaltoeachother
forareliableactivemeasurement.WhenbothUS-ESandUH-Earecloseto
zero,thentheHV-lineisnotinserviceortheoverheadgroundconductoris
completelycorrodedordisconnected.Inthiscase,thetotalpyloncurrentwill
bealsonearlyzero.
6. PresstheDISPLAYbuttonuntilISELappears.Thisisthetotalpylonearth
currentandismeasuredbythe4GroundFlex®sensors(channels1-2-3-4
selectedfora4legtower).
Figure 7 (model 6472)
Figure 6
Figure 5

GroundFlex®Adapter Model 6474 19
7. Next,presstheDISPLAYbuttonuntilRPASSappears.Aleakagecurrent
I-SEL,wheninducedinthepylon,producesavoltagedropUS-ES(potential
di󰀨erencetoEarth)ontheearth-resistanceofthepylon.OncetheI-SEL
andUS-ESvaluesareknown,the6472cancalculateRPASS(passive
earthresistance).Ithastheadvantageofbeingmeasuredatthenominal
frequencyofthenetworkbutisalsoinuencedbytheloaductuationsinthe
networkandbythepotentialinuenceoftheHV-line.Whenthetowerearth
resistanceisactivelymeasuredandisnearlyequaltoRPASS,theresultwill
bereliable;otherwise,thepotentialrelationshipduringtheactiveandpassive
measurementwillbedi󰀨erent.
Figure 8 (model 6472)
Second check (See Figures 9):
1. CurrentsinthetowerlegsaremeasuredcontinuouslyaslongastheSTART-
buttonhasnotbeenpressed.Switchthemodel6474toINPUT1.SelectISEL
on6472withDISPLAYbutton.
Figure 9
2. Checkthecurrentineachtowerlegbyswitchingthrougheachchannelin
sequencewhilenotingthemeasurementsofeach.Youcanndcorroded
and/ordisconnectedearthconnectionsasindicatedbyreadingsthatshowno
currentow.
3. Checkthesumofalllegcurrentchannels.Ifthetotalisapproximatelyequal
tothesumoftheallindividuallegcurrents,thenthestaticwire(overhead
groundconductor)isbondedtothetowerproperly.Ifnot,thisconnectionis
probablycorrodedandonlyasmallcurrentwillbeowinginthetowerlegs,
whichwillbeinducedinthetowergrounding.Thesumwillbeverylow,but,
despitethat,singlecurrentsmaybehigherbecausetheycanowindi󰀨erent
directions.ThemeasurementofRPASSforindividuallegshasnovalue.
Evenwhenindividuallegsarenotconnectedtogether.Belowgroundlevel,
theywillstillinuenceeachother.